Orthopedic casts and splints are frequently used in the treatment of both humans and other animals where it is necessary to inhibit motion of a limb which has sustained a fracture, for example to prevent bending of the limb at a joint. They are also used, particularly in the veterinary field, to protect wounds even in the absence of a fracture, to allow them to heal without being subjected to additional trauma which can hinder the healing process. The term cast is used herein to refer generally to a rigid article which completely encircles a limb or other body part. Thus, casts typically cannot be removed without cutting or otherwise destroying the integrity of the cast. In contrast, the term splint is used to refer to a rigid article which can be removed from the body part in one piece.
In the veterinary field, splints tend to be preferred over casts for treating fractures because the great majority of the cases of limb fractures are caused by blunt force trauma, and accordingly there typically is a tissue wound associated with the fracture which must periodically be attended to during the treatment period. Thus, splints offer the advantage of being removable and replaceable to allow the practitioner to treat the wound and re-splint the limb.
In the treatment of humans, use of custom-shaped splints has increased because of the ability of the splints to properly fit the body part being treated so as to avoid pressure points against the body part. Such pressure points can cause a variety of problems, including pressure ulcers and the like. Patients tend to prefer custom-shaped splints also, because of the improved comfort they provide.
Various types of articles for forming custom-shaped casts, splints, or other body part protectors, have been developed for use by humans. Most of the currently available articles utilize a flexible strip or sheet of foam or fabric which is impregnated with a water-curable resin which cures and hardens within a relatively short time after being exposed to water. The strip or sheet in some cases includes a protective and cushioning cover such as foam or fabric. The strip or sheet is soaked in water, and is then wrapped or otherwise applied to the body part being splinted. The cast or splint is allowed to cure while applied to the body part, and the result is a rigid splint which substantially conforms to the shape of the body part.
Prior to the present invention, however, most of the splinting and casting articles and methods have been oriented toward splinting materials which are limited in the extent to which they can be modified in size for properly fitting a body part to be splinted. Furthermore, most of the splinting methods have not been well suited to emergency use in the field, where materials and time may be limited.
For instance, U.S. Pat. No. 5,334,442 discloses an orthopedic sheet-like composition for forming a cast or splint which comprises an inner pliant sheet impregnated with a water-curable resin, and a pair of composite fabric portions contacting at least one side and covering both sides of the pliant sheet. The composite fabric portions comprise triple-layered knit fabric. In one disclosed embodiment, a layer of closed-cell foam is adhered between one of the composite fabric portions and the pliant impregnated sheet, and a double-sided adhesive tape is applied between a peripheral area of the other fabric portion and the pliant impregnated sheet, so as to prevent dislodgement of the pliant sheet, the fabrics, and the closed-cell foam material. The sheet-like composition is stored and sealed within a package filled with inert gas. Just prior to use, the package is opened and the composition is removed, and the composition is dipped in water briefly and then removed from the water and shaken to remove excess water. The composition is then applied to the body part and deformed by hand to conform to the body part. It will be appreciated that a pre-fabricated structure having a fixed length and width such as that disclosed in the '442 patent may not be suitable for making a custom-fitted splint in the field. For instance, where the width of the structure exceeds about half the circumference of the body part to be splinted, a splint made from the structure will wrap more than halfway around the body part and hence will not be removable to permit inspection of and treatment of the injury site. Because the composition disclosed by the '442 patent comprises a unitary structure held together at its periphery, it is limited in the extent to which it can be modified by the practitioner in the field to adapt the size, and particularly the width, of the composition, to the particular body part to be treated.
U.S. Pat. No. 3,900,024 discloses an orthopedic cast and method of making the same, in which a first sheet of deformable water absorptive resilient material, preferably foam rubber or urethane foam, is placed on a working surface and trimmed to the appropriate size, and a number of sheets of gauze impregnated with dry plaster are individually placed over the first sheet in general alignment therewith. A second sheet of the water absorptive deformable material is trimmed to the appropriate size and placed over the plaster sheets. The two outer sheets are sized so that the peripheral edges of the sheets extend somewhat beyond the edges of the plaster sheets. These peripheral edges of the outer sheets are joined together such as by adhesive so as to form a sandwich construction or blank. The blank is saturated with water and excess water drained and pressed from the blank, and the blank is then applied to the body part. The necessity of preparing and individually placing a number of plaster-impregnated gauze sheets on the lower foam sheet, and then adhesively joining the upper and lower foam sheets together along their edges, makes the method of the '024 patent time consuming. Additionally, a practitioner in the field may not always have adhesive available. Accordingly, the method is not well suited for emergency use in the field where time and availability of materials may be limited.
U.S. Pat. No. 5,454,780 discloses a custom body protective device, such as a shin guard or the like, which comprises an initially flexible intermediate layer of fiberglass fabric impregnated with water-curable resin, and a pair of outer cushion layers of foam material laminated to a heavy knitted coating. The edges of the outer cushion layers are stitched together to enclose the resin-impregnated intermediate layer, forming a pre-fabricated product. The device is exposed to water and applied to a body part and is allowed to cure to form a protector for the body part. The protector may be secured to the body part by a strap having hook and loop fastener members. U.S. Pat. No. 5,544,663 discloses a protector similar to that of the '780 patent, and further discloses that patches of non-woven loop material can be sewn onto the outer surfaces of the cushion layers for cooperating with patches of hook material attached to opposite ends of an elastic strap to hold the protector on a leg. The pre-fabricated protectors of the '780 and '663 patents are not readily modifiable in size and shape, since trimming off a portion of the protector would remove the edge stitching and thus destroy the desired integrity of the structure.
Another problem associated with veterinary uses of splints is that many types of animals will chew at or try to remove a splint that causes discomfort to the animal because of poor fit, and in the process the animal may do additional damage to the area of treatment. Further, if the animal succeeds in removing the splint, additional injury and/or impairment of the healing process may likely occur. Pre-fabricated splints frequently do not fit properly, and therefore have the potential to cause discomfort and the aforementioned problems attendant thereto.
Furthermore, because animals may attempt to remove a splint, the fastening of the splint to the animal's body part must be such as to resist the animal's attempt to remove it. Fastening systems which may be suitable for use by humans, such as an ordinary bandaging material wrapped around the splint to hold it in place, are typically not well suited to use on animals. Additionally, and as previously noted, since a veterinary practitioner may wish to periodically remove a splint to treat an associated wound and then replace the splint, the fastening system should be convenient in its use. Thus, there is a need for splints and splinting articles for custom-shaping of splints having adequate fastening systems for use in the veterinary field.